When 7 Becomes 13
by HelenaGroy
Summary: Imagine what would happen if the Avengers were demigods. Imagine what would happen if they were put on the Argo II for a few weeks. Basically the seven and the Avengers getting to know each other and despite the age difference, becoming friends. Lots of humor and fluff, some angst.
1. Chapter 1

**A/N: This story takes place in an alternate universe where the Avengers are demigods. So if you haven't read the Percy Jackson and the Heroes of Olympus series than you will not understand any of this. I will be alternating between Natasha and Annabeth's POVs in a similar way to the HoO series. Also I have no experience writing Thor, so bear with me guys!**

**Disclaimer: I own nothing-it all belongs to Marvel and Rick Riordan.  
**

Chapter 1-Natasha

**10:00am, Triskelion, Washington DC**

Natasha looked over her bags, mentally double-checking that she had packed everything she would need for the next few weeks. Once she was positive she had everything, she locked up her apartment and went out of the building. She jumped in her car, a gorgeous black convertible Maserati, and headed to the SHIELD base. A few minutes later her phone started ringing.

"This is Romanoff." she answered as she put the call on speakerphone.

"Hey, Tash, it's me."The caller replied.

"Oh, Clint. Hey. Why are calling from your SHIELD phone?" Natasha instantly relaxed when she heard her partner's voice at the other end.

"My other one's dead. Go figure, right when we have to leave on a mission."

"You didn't think to charge it last night?"

"I did, but I've been working since four this morning, so the battery ran out. "

"Oh, so that's why you were up so absurdly early. I was thinking of getting up to ask you where you were going but there was no way I was getting out of bed at that time of the morning, so I just assumed you were working. Did Coulson have you doing more paperwork?"

"I actually think he makes up all of this shit just to torture me." Clint groaned.

"You know that if you just did the paperwork when he gave it to you you would never have this problem." Natasha said, chuckling a little.

"I know, I know. But it's so boring!"

"Quit whining, Barton. So, any idea what this mission is about? All I got was a text from Fury telling me to get my ass on base and to pack a bag with enough stuff for the next two or so weeks."

"Yeah, he sent me the same text earlier this morning. I packed before I left though so I don't have to go back to the apartment. I'm on my way to the briefing now and it seems like it's an Avengers mission because I just saw Thor coming down in the elevator and there's no reason he'd be here otherwise, but apart from that I don't really know what it's about."

"Well, that's weird. Fury usually tells us if he's calling in the whole team. Okay, I'm coming in now so I'll see you in a sec."

"Okay, bye."

"Bye." Natasha said as she ended the call.

She quickly parked the car, grabbed her bags and walked into the building. Natasha was waiting for the elevator when the main doors were thrown open and Tony Stark strutted in in his usual overly dramatic way. His entrance got mixed reactions, a few of the newer agents who were not used to him and his antics looked shocked and somewhat star struck, but most just rolled their eyes and ignored him.

"Morning, Red." he said as he joined Natasha by the elevator. "What cha doin' here?"

Natasha had learned early on to just ignore Tony's nicknames, but that didn't make them any less annoying. "I work here, Stark, in case you forgot." Natasha replied coldly as they got in the elevator.

"Yeah, I know, but why are you here on a Saturday?"

"People like me don't get to choose the hours we work. I'm guessing you're here for the mission briefing? Though I expect you've hacked the database so you probably know whatever you need to already."

"Believe it or not, I was locked out of the mainframe." Tony pouted. "Even Jarvis couldn't hack it."

"Well, then I guess you'll just have to find out with the rest of us." Natasha said, actually somewhat surprised that he hadn't been able to hack into SHIELD's mission files. It was relatively easy to do if you knew how. And yes, Natasha spoke from experience.

They got out of the elevator and walked down the hall into the briefing room. When they arrived, they saw that the rest of the team plus Fury was already there.

"Nice of you two to join us." Fury said as they entered. "Now we can get started."

Natasha went and sat down in the seat next to Clint. "Hey," she greeted him, "found out anything yet?"

"Nope, he's being really secretive, hasn't let anything slip." Clint replied.

"Hmm, weird. You know Stark wasn't able to hack the mission file?" Natasha told him.

"Really? Wow, that is strange."

"So, Avengers." Fury addressed the group. "By now you are all probably wondering what this mission is about and why everyone is being so secretive about it." The team nodded and looked at him with anticipation. "As you discovered in the events leading up to the battle of New York, not only are you a group of remarkable people, but there is something that makes you even more remarkable and powerful. You are demigods."

Natasha was somewhat disappointed by this answer; they already knew they were demigods. Why was Fury telling them again? It had been revealed to them two years ago before the battle of New York, when Fury had told them about the gods, that they were all demigods and that there was a secret war taking place in Manhattan and that the fighting demigods were in desperate need of reinforcements. The team was sent to help the younger demigods fight the titans who had joined forces with Thor's brother Loki and his Chitauri army.

After the second Titan War, most of them, Thor excepted, tried to ignore the fact that they were demigods and live normal lives, or as normal as superheroes or SHIELD agents could. But that could only last so long. Eventually people would start to notice things; the fact that Fury didn't seem to age or die, that abnormally strange things had started happening to some of the world's mightiest heroes. The Mist managed to hide most of the monsters and weird occurrences, but still, you could never know what people would see. And once people knew something was up then there would be hell to pay.

Steve piped up to voice what everyone was thinking. "We _are _aware of that Sir. Why are you reminding us?"

"Because Rogers, the team being demigods is essential to this mission." Fury replied, only half answering the question.

"We understand that Sir but-" Steve got out before he was interrupted by Tony.

"WHAT IS THE MISSION?!" Tony yelled, making everyone jump slightly.

"Jeez, Tony, chill." Bruce said, trying to calm the crazy billionaire.

Fury sighed and started again. "Annabeth Chase, daughter of Athena, and Percy Jackson, son of Poseidon. You may remember them from when you fought in the Titan War, without them the titans almost definitely would have won. Piper McLean, daughter of Aphrodite. Leo Valdez, son of Hephaestus. Jason Grace, son of Jupiter. Hazel Levesque, daughter of Pluto. And Frank Zhang, son of Mars. These young demigods are the seven from the Great Prophecy."

"Wait, the Great Prophecy. You mean:

_Seven half-bloods shall answer the call,_

_To storm or fire, the world must fall,_

_An oath to keep with a final breath,_

_And foes bear arms to the Doors of Death. _

That one?" Natasha asked.

"Yes, that's the one. Currently the seven are travelling to Athens for the final battle with Gaea and the giants in their flying ship called the Argo II. However, two of their crew members, Gleeson Hedge, a Satyr and their adult chaperone, and Nico Di Angelo, son of Hades, have just left to return to the Greek camp to try and prevent the imminent war with the Romans, thus leaving the seven unchaperoned and in desperate need of reinforcements."

"So you're saying you want us to babysit?" Clint asked doubtfully.

"Those aren't exactly the words I would use, but yeah, that's about the gist of it. The poor kids need help; they're out in the world alone with nowhere near enough training, on their way to fight a crazy earth goddess and her army of giants. You guys would be a huge help to them and could possibly turn the tide of the war." Fury explained. "Besides, two of their team members just came back from a literal trip through hell and are dealing with some serious PTSD. I know most of you are experts at dealing with that, so you could help them get over it in time for their battle."

"How long have they got before this battle?" Natasha asked.

"They've got fourteen days get to Athens." Fury answered.

"Well, I'm in." Natasha announced. "Annabeth is my half-sister, I should help her out."

"I'm in too." Clint said. "It sounds like these kids are in some deep shit; they need all the help they can get."

"I'll come too." Steve said as he stood up.

"Not sure how much help I'd be, but I'm willing." Bruce offered.

"I shall do my best to provide help and protection to the young godlings." Thor promised.

"Okay, so when do we leave." Tony asked, standing up with the rest of them.

"I assume you've all packed like I asked?" Fury addressed the group again. Everyone nodded their heads in confirmation. "Good, then you'll be leaving right now. You'll take Stark's plane to meet the crew of the Argo II Greece. From there you'll join them on their ship for the rest of their quest. Good luck." He walked out of the briefing room, leaving the team to make their own way out to the jet.

**A/N: So what does everyone think? Please let me know! Also, this story will be mostly humor and fluff (the first two chapters are just boring but necessary introductory stuff) so I will be taking suggestions if anyone has got something they would like to see happen. **

**Helena :)**


	2. Chapter 2

**A/N: So, here is the next chapter! Unfortunately I'm going back to school tomorrow so the updates will probably be further apart, but I will try to make them every 3-5 days. Enjoy! :D**

Chapter 2-Annabeth

**6:00am (earlier the same day), the Argo II, somewhere over Greece**

Annabeth walked out on to the deck. She looked out at the sunrise as she tried to calm her breathing. She had been woken up by her nightmares; they had been plaguing her all night. She knew that her dreams and nightmares would only get worse after her and Percy's trip through Tartarus, but she hadn't thought they would get this bad.

It was too early for anyone else to be awake yet, so Annabeth just wandered around the ship thinking about what Coach Hedge had told her before he left yesterday. He had said that because he was leaving with Reyna and Nico he had called in for backup-whatever that meant- and that another team would be joining them on the Argo II the next day. The whole conversation had been rather cryptic and had left plenty of questions swimming around in Annabeth's head that was for sure. Why did Coach think they would need reinforcements? Who _were_ the reinforcements? After all, knowledge was power and Annabeth hated not knowing.

Just then she saw Hazel climb up on to the deck, rubbing her eyes groggily. "Oh, hey Annabeth." She greeted she noticed Annabeth.

"Morning Hazel." Annabeth replied. "How are you feeling, after… you know all the stuff that happened yesterday?"

"Probably nowhere near as bad as you are, but still, not too great." Hazel answered. "What about you?"

"Ah, you know, pretty horrible. But I'm really just glad to see the sun again." Annabeth said.

"Yeah, I know the feeling." Hazel agreed reminding Annabeth that Hazel had been stuck in the underworld for almost seventy years. Annabeth had barely made it out of the underworld still sane the time that she was there when she was twelve, how Hazel had stayed there for decades without going insane… She realised that her trip through Tartarus had brought her closer to Hazel, if only because now Annabeth understood what it was like to be stuck in the dark thinking that it was the end and you would never see the sky again.

"So," Hazel started, pulling Annabeth out of her thoughts, "I'm gonna go get some breakfast. You wanna come?"

"Um, sure." Annabeth replied. "I might go get dressed first though."

"Oh yeah," Hazel said just realizing that she was still in her pyjamas, "I should probably go change as well."

Both girls walked back to their cabins to get changed, meeting again ten minutes later in the mess hall to eat breakfast. When Annabeth got there she saw that Leo and Piper had also woken up and were sitting at the table eating breakfast while Leo tried to explain to Piper how the engine of the Argo II worked. Piper just wasn't getting it.

When Annabeth walked in their conversation stopped as they got up to greet her, both overjoyed that she was mostly okay and back on the ship with them. After receiving a hug from Piper and a fist bump from Leo, Annabeth sat down at the table with them and started eating breakfast, her three friends filling her in on all the things she had missed.

Eventually Percy, Jason and Frank came into the mess hall for breakfast and joined them around the table talking, laughing, eating and just generally having a great time all being back together again. That's when Annabeth remembered she had meant to tell the rest of the seven about what Coach Hedge had told her before he left.

"Hey guys," Annabeth addressed the group, "I hate to break up the party, but there's something I need to tell you all."

The seriousness of her voice got everyone's attention. "Is something wrong?" Percy asked quickly, ever the concerned boyfriend.

"No, nothing's really the matter, it's just something that Coach told me before he left. I thought I should let you guys know." Annabeth told them. The rest of the seven were all looking at Annabeth, focussing all their attention on what she was about to say.

Annabeth took a deep breath and started again. "Before he left Coach Hedge told that because he was leaving with Reyna and Nico, he had called someone to ask for reinforcements to be sent for us."

"Reinforcements?" Leo asked. "What, doesn't Coach think we're capable enough?"

"I'm sure that's not what he meant. I think he is just worried about us that's all. He wants to be here to help us, but since he can't he's sending someone he knows can." Annabeth said diplomatically.

This little bit of empathy from Annabeth was enough to silence the group for a few seconds. But soon Jason took it on himself to ask the question on everyone's mind.

"Did he say who he was sending, Annabeth?"

"No, he didn't." Annabeth announced to her disappointed friends. "He did say that there were six of them coming and that they would be coming sometime today."

"Six of them? That's gotta be overkill." Percy said. "We're fine as it is, we don't need six more people, they'll just get in the way."

"Actually," Annabeth addressed the group again, "I do have an idea of who he might have called in to help us, and if it is the group of people that I think it is, then they definitely won't get in the way. In fact they could change the tide of the war."

That got a better reaction. They were all practically exploding with questions at Annabeth's revelation.

"Who do you think they are?" Frank asked, jumping out of his seat.

"If they're coming today then they'll need rooms to stay in. How many of them did you say there were, Annabeth?" Leo asked already making arrangements in his head.

"Who could they be that they could change the war?" Percy asked doubtfully.

"Guys. Guys! WHOA, GUYS! LISTEN TO ME!" Annabeth had to yell to get the attention of her rowdy friends.

Everyone quieted down immediately when they heard Annabeth yell. She was scary enough as it was; no one wanted to mess with her when she was mad.

"Thank you." Annabeth said calming down quickly now that the group was listening to her again. "First of all I know you want to know who I think they are, but I'm not going to tell you because I don't want to get anyone hopes up."

"But-"Leo started to protest before Annabeth cut him off.

"No." Annabeth said, shutting him down before he could start complaining. "Now, second of all, the problem of sleeping arrangements is an important one. I think what will probably happen is that some people will have to share cabins."

"Share?" Piper asked "With whom?"

"We'll have to decide when they get here." Annabeth told her friend. She turned back to the group. "But last of all to answer Percy's question, if you really thought about it then you would probably know who I was talking about and that would be all the answer you needed."

"Wait, do we know them, Annab-"Percy started to ask before he was interrupted by a loud thump from up on the deck.

Everyone froze.

"Uh, what was that?" Jason asked.

Annabeth stood up. "I believe that would be our reinforcements."

**A/N: What do you guys think? Please tell me! Also last time I forgot to include the link to my Polyvore; I have a set for each character in this story and will be adding new ones every few chapters. Just go to helenagroy on Polyvore and it should be there, if you can't find it please let me know and I can post a better link.**

**Helena :)**


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